LeSkid

I know it's functional because when starting cold, it takes a couple minutes to warm up and climb to 150-175, which is where it stays. I'm just wondering because even crawling through traffic, it never goes up to 200... 1/2 way on the gauge.

I was wondering so I just left it idling outside for a while and even after a good 5 minutes, it doesn't seem to get 'hot'. I know the non-electric fan is always turning but what's it take to overheat one of these things?

I read somewhere that the 'new' shape of hood back then improved cooling but does this sound normal to you guys?

Or is my gauge ca-ca?

...Roger...

If you dont trust your gauge you can test it using a temp gun. If you have a good cooling system it can maintain thermostat temps.

SEVNT6

Mine will hit 200 on a hot day, but if it's cool out it won't even hit 170....

And it's been like this for 30+ years.........

coconut vette

is it true that 350 chevy runs best around 200 or so for complete combustion? One of my friends keep telling me that i am running too cold @ 150???

...Roger...

Many of the $25 senders that are being sold are reading 30+ degrees colder than the engine actually is.
Meaning your 170 could be 200.... and your 200 could be 230+

Another note.. I'm finding that the original senders are also reading 30+ too cold. I took one of the original senders apart and cleaned it up and it went back to reading accurately.

I would check your engine temp with a temp gun to be sure.

7T1vette

A clean and properly configured 'stock' cooling system will keep the engine temps below 200F (using a 180F thermostat) in all but very hot conditions. Your gauge 'behavour' appears to be normal...but the reading on the gauge could be in error, depending on the accuracy of the temp sender.

Take your car to one of the auto parts stores and ask them if they have an infrared [IR] gun that they can use to measure the temp on your engine. (They have 'loaner' tools for folks that buy their parts, so you shouldn't have to buy one just to get a quick check. Call ahead to find out who can do this for you.) Leave car idling, raise hood and point the device at the water outlet housing on the intake manifold. If the reading is within 20F of what your gauge says, be happy...close enough.

P.S. The engine will run fine with water temps anywhere from 140F to 220F. It will burn more fuel and have different surface wear characteristics at different temps; but from 160-200F there are minor effects. The Chevy SB V-8 engine was designed to be run at 180F for the optimum temp performance. Later...due to EPA requirements...engines got 195F stats, so that more hydrocarbons would be burned off [that was just 5F below the maximum temp the car companies would allow for their engines due to potential warranty problems from overheating and damage].

SEVNT6

Roger........what do you think of this. When my Vette was new it always ran around 200/220 which I thought was pretty hot. If I remember right, it came with a hot thermostat.....like a 200. So I put a 160 thermo in & that dropped it down to 180. A few years later it started running cold. Damn thing wouldn't go over 160, so I put a 180 thermo in and that brought it back up.....

It still has the original sender. Do you think this could of been the problem all along?.......

...Roger...

My first thought be the 160 stat was sticking open since the 180 brought it back up.
Its possible the sender is beginning to fail. When the components inside the sender start getting dirty and don't make good contact it will cause the gauge to read cooler.
The car I'm working on now has an original sender ,54000 miles, the therm housing reads 185 with a temp gun but the gauge shows about 150 (just below the first mark).
I'll put inline on the green wire a 79 ohm resistor to check the gauge for a 210 reading and if thats OK then I'll install a 203 sender.

coconut vette

30 + is a big gap. Never knew that. Good information to have as that can do some damage. Is there a sending unit for vettes thats a better quality and close to accurate? I have a 77' probably the same as LeSkid's 76'.

...Roger...

I've been using the BWD WT203 from Orileys for $5.99.

Advance has the WT203 for $18
and the WT203Z for $6.29

Both numbers are the same sender and work very well.

coconut vette

Thanks Roger, for the info. I'll look them up.